While passing in front of the milky way, scientists caught the trace of what might be considered the first-ever 'rogue' black hole. This discovery is not only significant but also unambiguous as astronomers had theorized this isolated black hole almost 13 years ago but it remained undetected. The detection for the same was only possible with the sheer possibilities of a unique method termed 'Gravitational Microlensing'. This research for the same has been published on the online preprint server arXiv, but is yet to be peer-reviewed.
But like how Rome
was not built in a day, neither was this discovery strenuous but it took almost
six years of intense data collection via an observation campaign chaired by
Kailash Sahu and his coworkers. Those six years of tenaciously assembled data
all started back in 2011, when a star about 20,000 light-years away illuminated
unexpectedly through the power of the Hubble telescope. It is supposed by
scientists that the black hole was created around 100 million years ago, but
data regarding the same is unclear due to its intractability and this was all
that researchers belonging to the concerned fraternity were looking for.
How did astronomers discover the Rogue Black Hole?
While guiding its
way through the milky way and passing in front of a background light source,
this one of a kind 'rogue' black hole got detected. This was only made possible
due to the intense gravitational force that the black hole carries with itself
which bent the light of the background star it was passing in front of, further
leading to its discovery. It is pertinent here to note that the black hole is a
tad bit over 5,000 light-years ahead of our planet. Scientists have further
detected that the 'rogue' black hole has been captured, travelling at a speed
close to 45 km (28 miles) per second. But what led to scientists finding this
indigeneity? We’ll all this was made possible through 'gravitational lensing'
What is Gravitational lensing?
Gravitational
lensing is the bending of light in the presence of the abrupter gradients of a
gravitational object like a galaxy, black hole, or even a star. Generally,
light travels in a straight path. However, when one observes light extremely
critically, one can notice that massive objects curve the space-time through
which light travels. This also has the effect of causing the light to be
redirected to a small yet measurable degree. Gravitational lensing is unique as
it allows astronomers to observe invisible things in the Universe.
This discovery is
significant as Isolated local black holes are therefore much, much harder to
detect as there are likely hundreds of millions of black holes in the Milky Way
and as the color of these black holes go by their names finding them becomes
extremely difficult. Back in 2011, the Microlensing Observations in
Astrophysics (MOA) in New Zealand and the Optical Gravitational Lensing
Experiment (OGLE) in Chile had spotted the same black hole but they didn't have
much data to prove it.